NOTES UN AUTINU'I'RUOHA. 



Notes on Actinotrocha. 



By 



K. Kaiiiiiiiiii Mellon, 



Assibiani I'rofessor, Prcsideucy College, Madias 



With Plate 26. 



Thk fulluwing notes on Actinotrocha (a careful comparison 

 of which with Brachiopod larvto seemed desirable) may bo of 

 interest in connection with Masterman's recent investigations 

 on this larval form. I wish to express here my deep indebt- 

 edness to my kind teacher, Professor Bourne, for affording 

 me every facility and help for working inhis laboratory. 



The larva? which were caught during the latter part of 

 October last belong to three different species, none of which 

 I have been able to identify. One of these, which is very 

 rare (owing, perhaps, to its being only an occasional immi- 

 grant into the surface water), has a short, thick body, short 

 tentacles, a small hood, and a strong perianal band, and, if 

 the conspicuous broad pigmented zone round the body may 

 be regarded as affording a clue, probably belongs to 

 Phorouis australis. The second species is much longer, 

 has longer tentacles, a well-developed hood, and a transparent 

 body-wall. My observations are based mainly on this species. 

 The third species is much smaller than the second, and but 

 for the fact that it metamorphoses directly into the young 

 Phoronis, would be regarded as a young stage of the second. 

 The larvas were preserved in corrosive sublimate, osmic acid, 

 and chromo-aceto-osmic mixture, cut in celloidin and stained 

 with hiomalum. 



